One objective of this work is to fractionate antigens from stains of Shigella which do and do not trigger Reiter's disease in HLA-B27 positive individuals. The fractionation procedures will be used to isolate protein or carbohydrate antigens which exhibit compositional differences between the bacterial strains. Bacterial antigens obtained in this manner will be tested and compared for their ability to elicit an immunological response in B27 positive patients who have developed Reiter's disease versus B27 positive patients who had shigellosis but did not develop Reiter's disease. In brief, the stimulation of lymphocytes by bacterial antigens and the presence of antibody against bacterial antigen or B27-associated with bacterial antigen will be tested. A second objective of this work is to isolate and purify B27 antigen from the urine of kidney transplanted patients. The purified B27 antigen will be used directly in further tests, and will be used to produce xenoantisera. An ELISA and/or radioimmunoassay for B27 will be developed using either alloantisera or xenoantisera. The resulting immunoassay will be used in tests on the serum, urine, and possibly the tissue of patients with Reiter's disease.